discourse/discourse — pull request #1805 by shivpkumar (2014-01-09 23:21:25+00:00)
Title: username characters validation error should include underscores

According to the `username_validator.rb`, the `username_char_valid?` method checks that the username only includes letters, numbers or underscores. The error received when trying to add any other characters to the username currently reads "must only include numbers and letters". Simply updating this error message to include underscores, since those are also allowed.

![categories_list_-_community_forum-3](https://f.cloud.github.com/assets/3858670/1883336/baec9ab2-7984-11e3-9bdb-605350aee4bd.gif)